Jonathan Rowe has written a great commentary for the Christian Science Monitor:
Tollbooths of the mind.

Share money and you have less; share an idea and you still have it, and more. Jefferson practiced what he preached, in this respect at least. As the nation's first commissioner of patents, Jefferson did not grant these monopolies easily or eagerly. He accepted the need for copyrights and patents, but strictly limited in extent and time.

The aim always was to enrich the public domain – the commons of the mind – not to line the pockets of a privileged class of monopolists of ideas. Jefferson actually refused to patent his many inventions, because he believed invention to be the property of humankind.

This vision prevailed in America for two centuries, more or less. The result was more enterprise, research, and invention than the world had ever seen. The nation had its share of patent hounds, Thomas Edison not least of them. But in the realm of science, the Jeffersonian ethos prevailed. Jonas Salk, who discovered the first polio vaccine, once was asked who would own the new drug. "There is no patent," Salk replied. "Could you patent the sun?"

Today, that question would not be rhetorical. Fences and tollgates are rising rapidly on Jefferson's commons of the mind. Copyright and patent monopolies have gone far beyond what he and other Founders intended. Corporations now are claiming ownership of everything under the sun, if not the sun itself: body parts, business practices, the genetic code. They even are claiming ownership of the English language. McDonald's has asserted trademark claims to 131 common words and phrases, such as "Always Fun" and "Made For You."